Technological Field
The present disclosure relates to an image formation apparatus and particularly to control of a charging apparatus.
Description of the Related Art
In general, an image formation apparatus (a printer, a copying machine, and a facsimile machine) making use of an electrophotographic process technique forms an electrostatic latent image by irradiating (exposing to light) a charged photoconductor with laser beams based on image data. Then, the electrostatic latent image is visualized by supplying toner from a development apparatus to the photoconductor on which the electrostatic latent image has been formed, and a toner image is thus formed. The toner image is directly or indirectly transferred to paper, and thereafter the toner image is fixed by heating and application of a pressure in a fixing nip. The toner image is thus formed on the paper.
In an image formation apparatus of this type, proper adjustment of a charge potential at which a charging apparatus charges a photoconductor has conventionally been demanded. The photoconductor, however, is not constant in film thickness. When the film thickness decreases, the charge potential varies and an image may be poor or a line may be thin.
Japanese Laid-Open Patent Publication No. 08-185017 has proposed a scheme of sensing a charge potential at a surface of a photoconductor, predicting production of a poor image, and setting a charge bias voltage.